How to create a singleton service

Ionic Framework ionic-v3
6

Hey, can someone help me?

I’m trying to put 2 providers in my bootstrap, then all pages can use both correct?

Well, when i push a page in my app, this message appears:
Error in build/pages/login/login.html:19:16BrowserDomAdapter.logError @ browser_adapter.js:84
browser_adapter.js:84ORIGINAL EXCEPTION: Can’t resolve all parameters for HomePage: (NavController, App, MenuController, LoadingController, Services, ?).

Someone know why?

Thanks!